Features of Forming a Structure of the Copper-Zinc Alloy Coating on the Aluminum Alloy Surface by Friction Stir Processing

The structure of samples of the C27400 copper alloy coatings on the AA5056 aluminum alloy surface, produced by friction stir processing of a rolled sheet package is studied. The regularities of the structure formation at deformation-initiated mixing of Al–(Cu, Zn) system components are elucidated. Intensive diffusion and mechanical mixing of the Al–(Cu, Zn) system components is revealed, resulting in the formation of a complex structure of the stir zone on the macrolevel. It is established that during the formation of the structural-phase composition of the coating, the solid aluminum solutions are formed in copper by zinc extrusion from the solid solution together with complex solid solutions and intermetallic phases by zinc diffusion into the aluminum lattice.